Idaho Code § 42-2818
After the construction of any such public drainage or irrigation project within the state of Idaho under this chapter, and until the board of county commissioners shall have made a suitable contract with some existing irrigation or drainage district, or ditch or irrigation company for the operation and maintenance of said project, and in the case of irrigation projects for the distribution of the water supply made available from the reservoirs or other irrigation structure constructed or provided under this chapter to the lands in said county assessed for the benefits of such improvement, or in case no such contract is made with such district or company to act as the agency of the county for the distribution of the water and the maintenance and operation of the works, then until such time as the operating district herein provided for shall have taken over the operation and maintenance of said works in the distribution of water therefrom in the case of irrigation works and shall have provided the necessary funds for such operation, maintenance and distribution, the board of county commissioners of the county in which the lands assessed for the benefits of such irrigation or drainage project are located shall keep such works and all parts thereof in proper repair and shall make proper contracts and take all necessary steps to maintain and operate the same and pay the cost of such maintenance and operation, and in the case of irrigation projects to distribute the water made available by such works and provide for and pay the cost of such maintenance and operation, and in case there are public funds to the credit of the drainage or irrigation project so to be operated or maintained, to make such repairs and pay for such maintenance and operation, such fund may be expended by the board of county commissioners for such purpose without further assessment. In case there are no public funds to the credit of such irrigation or drainage project so to be operated and maintained, then except as hereinafter otherwise provided, the board of county commissioners shall pay for the same out of the general revenue funds of the county, and to raise the necessary money to reimburse that fund it is hereby authorized to apportion and assess the cost thereof upon all lands originally assessed for benefits by reason of the construction of said project, said apportionment and assessment to be in the same proportion as was the original assessment for benefits. Such board of county commissioners shall make a written statement of such assessment and deliver the same to the auditor of the county, who shall put the same upon the next succeeding tax record and tax roll of said county and who shall make and file in the office of the county recorder the lien statement covering the cost and expenses of such operation, maintenance and repair, and such assessment shall be a first and paramount lien upon the lands affected, the same as state and county taxes and shall be collected in like manner as the liens for the construction of the project, except that the same shall not be payable in instalments, but such operation and maintenance expense shall be provided for in each year's assessments. In case such assessment, or any part thereof is chargeable against lands in another county, then the amount thereof chargeable against such other county shall be the board of county commissioners of the county which has paid the same, be certified to the county auditor of such other county chargeable therewith, and such last-mentioned county auditor shall thereupon draw his warrant therefor in favor of and deliver the same to the county treasurer of the county which has paid the same, and such auditor drawing such warrant shall thereupon apportion and assess and file for the amount thereof upon all lands in said county originally assessed for benefits by reason of the construction of said project in the same proportion as was the original assessment of benefits.
Idaho Code § 42-2818